Some people just make better friends than lovers. If you can maintain a friendship then why not? You just both have to be sure that you are in it for the same reasons. You will have to be accepting of the fact that you will one day date other people and be okay with it. Even though feelings don't go away overnight, you still have to treat eachother like you would any other friend. Is that something you can both handle?

If so then go for it. If he is a good friend and is really able to be there for you then that is great. But if it will get messy if say you or him start seeing someone else then it may not be worth the potential hassle. Only the two of you will know this for sure. You best bet would be to have a really honest discussion about it to see where the other one stands.